Organic compounds -- part of the class 532-570 series – Organic compounds – Heavy metal containing
Reexamination Certificate
2000-01-20
2002-10-22
Nazario-Gonzalez, Porfirio (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heavy metal containing
C556S013000, C556S043000, C556S053000, C534S011000, C534S015000, C502S103000, C502S117000, C526S160000, C526S943000
Reexamination Certificate
active
06469188
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to catalysts, catalyst systems and methods of production of olefin polymers, including isotactic, syndiotactic and stereoblock polymer, and the polymers produced thereby.
BACKGROUND
The mechanical properties of a given polymer can generally be classified as rigid, flexible, or elastic. While metallocene catalysts are capable of producing polymers that fall into each of these classifications, the most intense efforts have been directed at surpassing existing systems in their aptitude for making rigid isotactic polypropylene and rigid or flexible polyethylene [1] More recently, growing efforts to devise metallocene catalysts capable of producing elastomenrc polymers have revealed several different viable strategies: ethylene/&agr;-olefin copolymers [2]; high molecular weight atactic polypropylene [3]; binary isotactic/atactic compatibilized polypropylene [4]; isotactic-atactic polypropylene [5]; stereoblock isotacticatactic polypropylene [6]; and isotactic polypropylene with controllable stereoerror sequences. [7] Although the structure/property relationship of each of these regimes is not fully understood, the elastomeric properties undoubtedly rely on the existence of physical crosslinks in the presence of an amorphous phase. In the case of high molecular weight materials, the crosslinks can be simple chain entanglements. In the other examples, segments from several different polymer chains participate in crystalline regions, which physically connect the chains and provide crosslinks in an otherwise amorphous phase.
One of the best understood systems is that initially developed by Coates and Waymouth. [6, 8] Their unbridged metallocene (2-phenylindenyl)
2
ZrCl
2
, in the presence of methylaluminoxane (MAO), isomerizes between chiral and achiral coordination geometries during the formation of a given polypropylene chain. Since the chiral isomer is isospecific and the achiral isomer is aspecific, stereoblock isotactic-atactic polypropylene is obtained.
Elastomeric and other polyolefins with controlled stereostructures are useful for a wide variety of applications. Novel polyolefins, especially those with elastomeric properties, can be useful for a wide variety of applications. Accordingly, there is a need for catalyst systems capable of polymerizing alkenes to novel polyolefins.
There is also a need to develop catalysts sufficiently stable to be used on an industrial scale. Owing to the chelate effect, bridged metallocene catalysts tend to be more stable at elevated polymerization temperatures, and often behave more predictably when adsorbed on a support, a common industrial tactic.
Accordingly, there is a need for stable, readily synthesized catalyst systems capable of controlled polymerization of alkenes to give polyolefins.
SUMMARY
The invention provides bridged metallocene catalyst systems that are useful for the controlled polymerization of alkenes to polyolefins. Also provided are catalyst systems useful for polymerizing a variety of alkene monomers into stereocontrolled polymers including isotactic polymers, syndiotactic polymers and stereoblock polymers containing both hemiisotactic and isotactic regions. Catalysts of the invention can be chosen to provide a specific size range of produced polymers. Catalysts also can be chosen so as to produce a polymer with a desired microstructure.
This invention describes a new catalyst system for polymerizing C
2
to C
10
alk-1-enes to produce polyolefin polymers. The catalyst system includes two components: (a) an organometallic compound of the general formula (II),
in which M is a metal of the III, IV, or V subgroup of the periodic system or a metal from the lanthanide or actinide groups; X is fluorine, chlorine, bromine, iodine, hydrogen, C
1
to C
10
alkyl, C
6
to C
20
aryl, alkylaryl, arylalkyl, fluoroalkyl, or fluoroaryl having 1 to 10 carbons in the alkyl moiety and 6 to 20 carbon atoms in the aryl moiety, or —OR
17
where R
17
is a C
1
to C
10
alkyl or C
6
to C
20
aryl; n is the formal oxidation state of M minus 2; E
1
is hydrogen, carbon, silicon, or germanium; E
2
is carbon, silicon, or germanium; R
1
, R
2
, R
3
, R
4
, R
5
, R
6
, R
7
, R
8
, R
9
, R
10
, R
11
, R
12
, R
13
, R
14
, R
15
, and R
16
are, independently, hydrogen, C
1
to C
10
alkyl, 3 to 10 membered cycloalkyl, which in turn may have from 1 to 10 C
1
to C
10
alkyls as substituents, C
6
to C
16
aryl or arylalkyl in which two adjacent substituents may together stand for cyclic groups having 4 to 16 carbon atoms which in turn may be substituted, or Si(R
18
)
3
where R
18
is a C
1
to C
10
alkyl, C
6
to C
16
aryl or C
3
to C
10
cycloalkyl; and where E
1
is hydrogen, R
1
, R
2
and R
3
are absent; or an organometallic compound of the general formula (III),
in which M is a metal of the III, IV, or V subgroup of the periodic system or a metal from the lanthanide or actinide groups; X is fluorine, chlorine, bromine, iodine, hydrogen, C
1
to C
10
alkyl, C
6
to C
20
aryl, alkylaryl, arylalkyl, fluoroalkyl, or fluoroaryl having 1 to 10 carbons in the alkyl moiety and 6 to 20 carbon atoms in the aryl moiety, or —OR
13
where R
13
is a C
1
to C
10
alkyl or C
6
to C
20
aryl; n is the formal oxidation state of M minus 2; E
1
is hydrogen, carbon, silicon, or germanium; E
2
is carbon, silicon, or germanium; R
1
, R
2
, R
3
, R
4
, R
5
, R
6
, R
7
, R
8
, R
9
, R
10
, R
11
, and R
12
are, independently, hydrogen, C
1
to C
10
alkyl, 3 to 10 membered cycloalkyl, which in turn may have from 1 to 10 C
1
to C
10
alkyls as substituents, C
6
to C
16
aryl or arylalkyl in which two adjacent substituents may together stand for cyclic groups having 4 to 16 carbon atoms which in turn may be substituted, or Si(R
14
)
3
where R
14
is a C
1
to C
10
alkyl, C
6
to C
16
aryl or C
3
to C
10
cycloalkyl; and where E
1
is hydrogen, R
1
, R
2
and R
3
are absent; and (b) an activator.
Catalyst System for Isotactic Polyolefins
Metallocene catalysts can be chosen according to the invention that produce isotactic polyolefins. The preferred catalyst for polymerizing C
2
to C
10
alk-1-enes to produce isotactic polyolefins is compound II or compound III wherein no elements of symmetry exist; that is, compound II or compound III are of C
1
symmetry. It is generally preferred that the R
1
, R
2
, R
3
, and E
1
group is a sterically large group, for example an adamantyl group. The preferred metals are titanium, zirconium, hafnium, scandium, and yttrium. The preferred X are chlorine, bromine, hydrogen, methyl, phenyl, and benzyl. The preferred E
2
is carbon or silicon. The preferred R substituents are as follows: For II, R
1
, R
2
, R
3
, and E
1
constitute the 2-methyl-2-adamantyl group; R
4
, R
5
, R
6
, R
7
, R
8
, R
9
, R
10
, R
11
, R
12
, R
13
, and R
14
are hydrogen; R
15
and R
16
are methyl, phenyl, or part of a cycloalkyl group, including cyclohexyl or adamantyl. For III, R
1
, R
2
, R
3
, and E
1
constitute the 2-methyl-2-adamantyl group; R
4
, R
5
, R
6
, R
7
, R
8
, R
9
, and R
10
are hydrogen; R
11
and R
12
are methyl, phenyl, or part of a cycloalkyl group, including cyclohexyl or adamantyl.
Catalyst System for Syndiotactic Polyolefins
Catalyst systems also can be prepared that preferentially catalyze the formation of syndiotactic polyolefins from alkene precursors. The preferred catalyst for polymerizing C
2
to C
10
alk-1-enes to produce syndiotactic polyolefins is compound III wherein a mirror plane of symmetry exists; that is, compound III is of C
s
symmetry. The preferred metals are titanium, zirconium, hafnium, scandium, and yttrium. The preferred X are chlorine, bromine, hydrogen, methyl, phenyl, and benzyl. The preferred E
1
is carbon or silicon. The preferred R substituents are as follows: E
1
is hydrogen, R
1
, R
2
and R
3
are absent; R
4
, R
5
, R
6
, R
7
, R
8
, R
9
and R
10
are hydrogen; R
11
and R
12
are methyl, phenyl, or part of a cycloalkyl group, including cyclohexyl or ada
Bercaw John E.
Miller Stephen A.
Bingham & McCutchen LLP
California Institute of Technology
Maher David W.
Nazario-Gonzalez Porfirio
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